By Megan Leonhardt

Law360, New York (January 13, 2012, 2:19 PM ET) -- Auction companies Christie’s Inc., Sotheby’s Inc. and eBay Inc. fired back Thursday against three proposed class actions filed by artists over resale royalties allegedly owed to them under the California Resale Royalties Act, arguing that the law is unconstitutional.

In motions to dismiss the punitive class actions brought by artists in California federal court, Christie’s, Sotheby’s and eBay contended that the Royalties Act violates the commerce clause of the U.S. Constitution by attempting to regulate interstate commerce.

“Because the CRRA expressly regulates commerce outside California, it...